Process for separating 1, 3, 4-xylenol and 1, 4, 2-xylenol from mixtures containing the same and organic base complexes derived therefrom



Patented Oct. 24, 1950 UNITED STATES tATENT OFFICE Francis E. Cislak and Merritt M. Otto, Indianapolis, Ind.

No Drawing. Application August 20, 1945, Serial No. 611,696

20 Claims.

Our invention relates to the separation of 1,3,4- xylenol (1,3-dimethyl-4-hydroxybenzene) from mixtures containing 1,3,4-xylenol and 1,4,2-xylenol (1,4-dimethyl2-hydroxybenzene) with the 1,3,4-xylenol predominating.

It is the object of our present invention to obtain the individual 1,3,4-xylenol; and to obtain new compounds of 1,3,4-xylenol and an organic base.

A mixture of 1,3,4-xylenol and 1,4,2-xylenol, associated with various other phenolic bodies, is obtained in the processing of coal tar and of petroleum. The other phenolic bodies commonly present, including paraethylphenol, can be separated quite readily and fairly completely from the mixture of 1,3,4-xylenol and 1,4,2-xylenol by fractional distillation. But the boiling points of the 1,3,4-xyleno1 and the 1,4,2-xyleno1 are so close together that it is not commercially practical to separate them by fractional distillation.

We have found that by treating with an organic base of the class of Z-methylquinoline, 4-methy1- quinoline, 8-methylquinoline, aniline, 3-methylaniline, 4-methylaniline, and 2,6-dimethylpiperidine a mixture of 1,3,4-xylenol and 1,4,2-xy1enol containing more than about 55% or more than about 65% 1,3,4-xylenol, whether or not the mixture also contains small amounts of higher and/or lower related phenolic bodies (such as the cresols ing with S-methylquinoline or with aniline or with l-methylaniline or with 2,6-dimethylpiperidine the cooling is desirably to a temperature at least as low as about -5 C. but rarely needs to be below 15 0.; when treating with 2-methylquinoline Or with 4-methylquinoline or with 3-methylaniline the cooling is desirably to a temperature as low as about 10 C. but rarely needs to be below about -10 C. The crystals in any of these cases can readily be recovered, as by decanting or filtering; and can readily be reconverted into substantially pure 1,3,4-xylenol, and substantially pure organic bases (Z-methylquinoline or l-methylquinoline or 8-methylquinoline or aniline or 3-methylaniline or 4-methylaniline or 2,6-dimethylpiperidine) Upon the recovery of the crystals of 1,3,4-xylenolorganic base by the decanting or filtering above referred to, the mother liquor remaining is much enriched in 1,4,2-xylenol, in comparison with the original 1,3,4-xylenol-1,4,2-xylenol mixture; and also contains considerable organic base and some 1,3,4-xy1enol. This mother liquor may be used as a source of 1,4,2-xylenol.

The 1,3,4-xylenol-2-methylquinoline, 1,3,4- xylenol4-methylquinoline, 1,3,4-xylenol-8-meth ylquinoline, 1,3,4-xylenol-aniline, 1,3,4-xylenol- 3-methylaniline, 1,3,4-xylenoll-methylaniline, and l,3,4-xylenol-2,6-dimethylpiperidine, are new compounds; The approximate crystal points of these new products are tabulated below:

1,3A-xylenol-2-methylquinoline 29 1,3,4-xylenol-4-methylquinoline 41 1,3,4-xylenol-8-methylquinoline 15 1,3,4-xylenol-aniline 19 13,4-xylenol-3-methylaniline 29 1,3A-xylenol-4-methylaniline 21 1,3,4xylenol-2,6-dimethylpiperidine 14 Thes new compounds are of interest in the preparation of disinfectants and insecticides as well as in the present process of separating 1,3,4- xylenol from 1,4,2-xylenol.

The following examples illustrate our invention.

Example 1.10() pounds of a mixture of 1,3,4- xylenol and 1,4,2-xylenol, containing more than about 55 1,3,4-xylenol, is thoroughly mixed with about pounds of Z-methylquinoline and about 20 pounds of petroleum naphtha. The mixing can be done with the ingredients cold, orpreferablyrthe mixture may be cooled after the mixing, in either case to obtain a temperature of about -10 C. to 10 C. By such cooling the addition product 1,3,4-xylenol-2-methylquinoline, usually crystallizes spontaneously from the mixture, although sometimes it is necessary to start crystallization by seeding with crystals of 1,3,4-xylenoldistills over. As, so recovered the 1,3,4-xylenol is usually of about 90% to 95% purity.

In place of the 2-methylquinoline, we can use 4-methylquinoline or 8-methylquinoline.

Example 2.10O pounds of a mixture of 1,3,4- xylenol and 1,4,2-xylenol, containing more than about 65% 1,3,4-xylenol, is thoroughly mixed with about 100 pounds of aniline, and with about pounds of petroleum naphtha. The mixing can be done with the ingredients cold, or preferably the mixture may be cooled after the mixing, in either case to get a temperature of about -5 C. to 15 C. By such cooling the addition product, 1,3,4-xyleno1-aniline, usually crystallizes spontaneously from the mixture, although sometimes it is necessary to start crystallization by seeding with crystals of 1,3,4-xy1eno1-aniline. The crystals of 1,3,4-xy1enol-aniline produced by the cooling are suitably separated, most conveniently by filtration. Although it is not necessary to do so, we prefer to wash these crystals with a cooled inert solvent-such as a parafinic petroleum naphtharto remove any mother liquor adhering to the crystals. These crystals of 1,3,4-xylenolaniline are mixed with about 1'75 pounds of 10% aqueous caustic soda solution. This mixing with caustic soda solution decomposes the crystals of 1,3,4-xylenol-aniline into the sodium salt of 1,3,4-xylenol and aniline. The aniline is recovered from this caustic soda solution by steam distillation; when all the aniline has been steam distilled from the solution, the sodium salt of 1,3,4-xylenol is decomposed by acidifying the caustic soda solution, as with sulfuric acid, whereupon the 1,3,4-xyleno1 forms an upper layer and is separated from the lower aqueous salt layer as by decantation. The 1,3,4-xylenol, after drying, is usually of about 90% to 95% purity.

In place of the aniline, we can use 3-methy1- aniline, or 4-methylaniline, or 2,6-dimethylpiperidine.

In the above examples, we have used a molecular excess of organic base; this we deem desirable although not essential.

We claim:

1. The process of separating 1,3,4-xyleno1 from a mixture consisting mainly of 1,3,4-xyleno1 and 1,4,2-xylenol, with the 1,3,4-xylenol content being more than about 55% to 65%, which consists in mixing such a mixture with an organic base of the class consisting of Z-methylquinoline, l-methylquinoline, 8-1nethylquinoline, aniline, 3-methylaniline, i-methylaniline, and 2,6-dimethylp-iperidine, and producing in the resulting mixture a sufificiently low temperature to .form crystals of lfiA-xylenol-organic base, separating such crystals, and decomposing the crystals to recover 1,3,4-xy1enol in purified form.

2. The process of separating 1,3,4-xylenol from a mixture consisting mainly of 1,3,4-xylenol and 1,4,2-xylenol, with the 1,3,4-xylen0l content being more than about 55% to 65%, which consists in mixing such a mixture with a molecular excess of an organic base of the class consisting of 2- methylquinoline, 4 methylquinoline, 8 methylquinoline, aniline, 3-methylaniline, l-methylaniline, and 2,6-dimethylpiperidine, and producing in the resulting mixture a suificiently low temperature to form crystals of 1,3,4-xylenol-organic base, separating such crystals, and decomposing the crystals to recover 1,3,4-xy1enol in purified form.

3. The process of separating 1,3,4-xylenol as set forth in claim 1, in which the organic base is 2- methylquinoline.

4. The process of separating 1,3,4-xylenol as set forth in claim 1, in which the organic base is 4-methylquinoline.

5. The process of separating 1,3,4-xylenol as set forth in claim 1, in which the organic base is aniline and the 1,3,4-xylenol content is more than about 65%.

6. The process of separating 1,3,4-xylenol as set forth in claim 2, in which the organic base is 2-methylquinoline.

'7. The process of separating 1,3,4-xylenol as set forth in claim 2, in which the organic base is l-methylquinoline.

8. The process of separating 1,3,4-xylenol as set forth in claim 2, in which the organic base is aniline and the 1,3,4-xylenol content is more than about 65% 9. The process of producing a compound of 1,3,4-xylenol and an organic base of the class consisting of 2-methylquinoline, 4-methylquinoline, S-methylquinoline, aniline, B-methylaniline, 4- methylaniline, and 2,6-dimethylpiperidine, which consists in mixing the organic base and a mixture consisting mainly of 1,3,4-xylenol and 1,4,2-xylenol, with the 1,3,4-xyleno1 content being more than about 55% to 65%, and producing in the resulting mixture a sufficiently low temperature to form crystals of 1,3,4-xy1enol-organic base,

10. The process of producing a compound of 1,3,4-xylenol and an organic base of the class consisting of 2-methylquinoline, i-methylquinoline, B-methylquinoline, aniline, 3-methylaniline, 4- methylaniline, and 2,6-dimethylpiperidine, which consists in mixing a molecular excess of the organic base and a mixture consisting mainly of 1,3,4-xylenol and 1,4,2-xylenol, with the 1,3,4- xylenol content being more than about 55% to 65%, and producing in the resulting mixture a sufficiently low temperature to form crystals of 1,3,4-xylenol-organic base.

11. The process of producing 1,3,4-xylenol-2- methylquinoline which consists in mixing 2- methylquinoline and a mixture consisting mainly of 1,3,4-xylenol and 1,4,2-xylenol, with the 1,3,4- xylenol content being more than about 55%, and producing in the resultin mixture a low temperature and crystallizing 1,3,4-xy1eno1-2-methylquinoline from the resulting mixture.

12. The process of producing 1,3,4-xylenol-4- methylquinoline which consists in mixing 1- methylquinoline and a mixture consisting mainly of 1,3,4-xylenol and 1,4,2-xylenol, with the 1,3,4- xylenol content being more than about 55%, and crystallizing 1,3,4 xylenol 4 methylquinoline from the resulting mixture.

13. The process of producing 1,3,4-xylenol-aniline which consists in mixing aniline and a mixture consisting mainly of 1,3,4-xylenol and 1,4,2- xylenol, with the 1,3,4-xylenol content being more than about 65%, and crystallizing 1,3,4- xylenol-aniline from the resulting mixture.

14. The new compounds of 1,3, i-xylenol and an organic base of the class consisting of Z-methylquinoline, 4-methylquinoline, 8-methylquinoline, aniline, 3-methylaniline, 4-methylaniline, and 2,6-dimethylpiperidine.

15. The new compound 1,3,4-xylenol-2-methylquinoline.

16. The new compound 1,3,4-xylenol-aniline.

17. The new compound 1,3,4-xylenol-2,6-dimethylpiperidine.

18. The process of separating 1,3,4-xylenol from a mixture consisting mainly of 1,3,4-xylenol and 1,4,2-xylenol, with the 1,3,4-xylenol content being more than about 55% to 65%, which consists in mixing such a mixture with 2-methy1- quinoline, and crystallizing 1,3,4-xy1eno1-organic base from the resulting mixture, separating the crystals so produced, and decomposing the crystals to recover 1,3,4-xy1eno1 in purified form.

19. The process of separating 1,3,4-xy1eno1 from a mixture consisting mainly of 1,3,4-xy1eno1 and 1,4,2-xy1en01, with the 1,3,4-xy1eno1 content being more than about 55% to 65%, which consists in mixing such a mixture with 4-methy1- quinoline, and crystaliizing 1,3,4-xy1eno1-0rganic base from the resulting mixture, separating the crystals so produced, and decomposing the crystals to recover 1,3,4-xy1eno1 in purified form.

20. The process of separating 1,3,4-xy1eno1 from a mixture consisting mainly of 1,3,4-xy1enol and 1,4,2-xy1eno1, with the 1,3,4-xy1eno1 content being more than about 65%, which consists in mixing such a mixture with aniline, and crystallizing 1,3,4-xy1eno1-organic base from the resultin mixture, separating the crystals so produced,

6 and decomposing the crystals to recover 1,3,4=- xylenol in purified form.

FRANCIS E. CISLAK. MERRIT'I M. QTTO.

REFERENCES CITED The following references are or record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,795,382 Ulrich Mar. 10, 1931 1,830,859 Schotte et a1. NOV, 10, 1931 1,942,838 Semon 1 Jan. 9, 1934 1,980,901 Bentley et a1 1 Nov. '13, 1934 2,029,642 Semon Feb. 4, 1936 2,193,336 Lecher et a1 Mar. 12, 1940 2,321,036 Luten et a1. June 8,1943

OTHER REFERENCES Fieser and Fieser, Organic Chemistry (Heath and 00., Boston, 1944), page 529. (Copy in Patent Office Library.) 

9. THE PROCESS OF PRODUCING A COMPOUND OF 1,3,4-XYLENOL AND AN ORGANIC BASE OF THE CLASS CONSISTING OF 2-METHYLQUINOLINE, 4-METHYLQUINOLINE, 8-METHYLQUINOLINE, ANILINE, 3-METHYLANILINE, 4METHYLANILINE, AND 2,6-DIMETHYLPIPERIDIENE, WHICH CONSISTS IN MIXING THE ORGANIC BASE AND A MIXTURE CONSISTING MAINLY OF 1,3,4-XYLENOL AND 1,4,2-XYLENOL, WITH THE 1,3,4-XYLENOL CONTENT BEING MORE THAN ABOUT 55% TO 65%, AND PRODUCING IN THE RESULTING MIXTURE A SUFFICIENTLY LOW TEMPERATURE TO FORM CRYSTALS OF 1,3,4-XYLENOL-ORGANIC BASE. 